Great question. Visual exploration is crucial, especially in the early stages of the design process. I just wrote about tactics for establishing visual design direction in my book. Here's the issue:

Historically, visual designers have gone about this by creating full comps — often many comps — to feel out the aesthetic values of the organization. Throw some comps against the wall and see what sticks. As you might imagine, generating a slew of comps from scratch takes an immense amount of time and effort, and unfortunately much of that work finds itself on the cutting room floor. There must be a more efficient way.

In a successful pattern-based process, you're able to get a sense of what aesthetics the stakeholders value and what they don't value without having to do a ton of work. Using exercises like The 20-second gut test and creating artifacts like style tiles and element collages can help the client get a feel for the aesthetic direction without having to burn a bunch of time developing a slew of full comps.

There's no substitute for real collaboration and communication. Artifacts like style tiles and element collages won't be effective if they're not coupled with real conversations about the goals of the project and aesthetic values of the organization. In short: more talking, less blind comping.